The present invention relates to a system consisting of an automotive vehicle, preferably a golf caddy, and a transmitter.
The present invention is not only applicable to golf carts which so far have normally been steered as hand-drawn golf carts by a player on handles and have carried the golf bag including the golf clubs, but also to other vehicles for whose purpose it may be advantageous when the vehicles can automatically follow a movable transmitter.
U.S. Pat. No. 3,742,507 and U.S. Pat. No. 4,844,493 already disclose automatic golf carts which have a position finder with the aid of which they can automatically approach an associated transmitter carried by a player. The position finder of the prior-art golf carts consists, in the one case, of a high-frequency position finder and, in the other prior-art embodiment, of an infra-red position finder, but the two finders do not offer the possibility of determining the exact distance from the associated transmitter. The prior-art golf carts are therefore not able to approach the transmitter exactly up to a predetermined distance and to stand still automatically when said minimum distance is reached until the player moves again together with the transmitter. Hence, the prior-art golf carts are not suitable in practice.
U.S. Pat. No. 4,109,186 dicloses a radio-controlled guide and speed control system for a golf caddy which comprises spaced-apart receivers to receive magnetic energy signals from a movable energy source. The received signals vary according to the positions of the receiver relative to the energy source and are electrically processed to control separated motors which drive two wheels of the golf caddy so as to start, steer and stop the same.
U.S. Pat. No. 3,748,564 discloses a remote-controlled vehicle having a right and a left drive wheel which can be driven independently of two eletric d.c. motors, the vehicle being responsive to a control signal which is supplied by a portable transmitter carried by a moving person. The vehicle has an electronic control system comprising a receiver which receives the emitted control signal and derives therefrom a distance signal which corresponds to the distance between the person and the vehicle, and a position finding signal for the course of the vehicle relative to the person. An amplifier circuit converts the distance and position finding signals into control signals for the motors of the right and left wheels.